1. Field of the Invention
Modern technology is currently supplying the general public and the process industries with machinery which is designed to operate under a wider range of temperatures and under greater loads than previously available. In addition, many of the newer machines are designed to operate at extremely high speeds. Many of these machines require certain specific lubricating properties which are not available in conventional lubricants. Thus, modernization of high-speed and high-temperature equipment has strained the petroleum industry for the development of a generation of lubricants capable of satisfying the requirements of the new machines. For example, there has been an increased demand for lubricants capable of performing well at temperatures above 149.degree. C in high-speed bearings and gears for periods in excess of 500 hours. In addition, with the further development of the high-speed sealed bearings, the lubricant must be able to endure for the life of the bearing.
2. Description of the Prior Art
Arylcarbamyl-thickened greases from ureas and diureas which are prepared from a mixture of two different amines and one diisocyanate or a diamine and two monoiisocyanates are described in U.S. Pat. No. 2,710,840. An especially preferred grease disclosed in U.S. Pat. Nos. 3,102,097; 3,154,491; and 3,563,894 is made from bitoylene diisocyanate, p-chloroaniline, and p-toluidine. U.S. Pat. No. 3,374,170 shows the heat-treated combination of 2,4-toluene diisocyanate with p-toluidine in a molar ratio of 1:2 respectively as a suitable grease thickener. A polyorgano siloxane thickened to a grease consistency with a diazo compound and an arylurea wherein the arylurea may be the combination of 2,4 toluene diisocyanate, p-toluidine, and p-chloroaniline is described in U.S. Pat. No. 3,082,170 in Table II Example 0. As evidenced by these patents, the combination of p-toluidine, p-chloroaniline, and toluene diisocyanate and the molar ratio of p-toluidine to p-chloroaniline of up to approximately 1.46:1 are known. The particular molar ratio employed herein and the surprising extended functional life results obtained thereby have not been heretofore described.